RESUMEN
The present study was carried out in a native Brazil nut tree population (Bertholletia excelsa Bonpl., Lecythidaceae) to assess its genetic diversity and structure. Ten microsatellite markers were used to genotype 198 adult trees (B. excelsa). The population presented high genetic diversity and inbreeding absence rates. The empirical Bayesian method showed three distinct groups in the structure of this population. Molecular analysis of variance showed 98% variability within groups, and 2% between groups. The genetic divergence (FST) indicated little difference between groups; thus, suggesting efficient gene flow between the analyzed B. excelsa adult trees.
Asunto(s)
Bertholletia/genética , Genotipo , Polimorfismo Genético , Teorema de Bayes , Flujo Génico , Endogamia , Repeticiones de MicrosatéliteRESUMEN
The genus Theobroma found in the Amazon region is composed of 22 species, including Theobroma speciosum, better known as cacauí. These species are constantly threatened by forest fragmentation caused by human activities and require conservation strategies and management aimed at preserving them in their natural environments. The main objective of this study was to analyze the population structure and genetic diversity within and between natural populations of T. speciosum by using ISSR molecular markers to understand the population structure of the species. Four natural populations belonging to the Amazon rainforest (BAC, CRO, FLA, and PNA), located in the State of Mato Grosso, were selected. Amplification reactions were performed using 15 ISSR primers. A total of 101 loci were found, of which 54.46% were polymorphic at the species level. The BAC population showed higher genetic diversity (H=0.095 and I=0.144) and higher percentage of polymorphism (28.71%). The populations showed an FST value of 0.604, indicating marked genetic differentiation. The highest genetic variation was found between populations. Gene flow was low between populations, indicating genetic isolation between populations.
Asunto(s)
Cacao/genética , Variación Genética , Repeticiones de Microsatélite/genética , Filogenia , Conservación de los Recursos Naturales , Ambiente , Flujo Génico , Flujo Genético , Genética de Población , HumanosRESUMEN
The genus Theobroma, recently reclassified in the family Malvaceae, comprises some species with high economic potential, including the cupuí, Theobroma subincanum Mart., which has not yet been domesticated, and whose genetics and population structure are mostly unknown. This study aimed to assess the population structure and genetic diversity in natural populations of T. subincanum Mart., using inter-simple sequence repeat (ISSR) markers. A total of 59 individuals were sampled in three geographically separate populations, CFA, CMN, and CPT. Nei's genetic distance was estimated to characterize populations with the use of 13 polymorphic primers. The analysis of molecular variance revealed that the variability between populations (51.71%) was higher than that within populations (48.29%). Among the three populations, CPT showed the highest diversity index and percentage of polymorphism. The ISSR molecular markers were efficient and presented sufficient polymorphism to estimate genetic diversity in populations of T. subincanum Mart.